ChemInform Abstract: Interatomic Distances in the Stable and Metastable bcc and Omega Structures of the Transition Metals: Analysis of Experimental and Theoretical Trends and Correlations with Pauling′s Bond Lengths.

ChemInform ◽  
2010 ◽  
Vol 31 (2) ◽  
pp. no-no
Author(s):  
G. Aurelio ◽  
A. Fernandez Guillermet
Keyword(s):  
Transition Metals ◽  
Interatomic Distances ◽  
Bond Lengths

Distortion isomers of PtM, Pt2M, PtM2 and PtMM′ (M = non-transition metals) derivatives-structural aspects

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš
Keyword(s):  
Transition Metals ◽  
Structural Parameters ◽  
Bond Angles ◽  
Bond Lengths ◽  
Metal Atoms ◽  
Independent Molecules ◽  
Structural Aspects

Abstract An analysis of the structural parameters of PtM, Pt2M, PtM2 and PtMM′ (M = non-transition metals) derivatives shows that each complex contains two crystallographically independent molecules within the same crystal. The respective molecules differ by the degrees of distortion and exemplify the distortion isomerism. These are discussed in terms of the coordination with the platinum and the M atoms and the correlations are drawn among the metal atoms, donor atoms, bond lengths and bond angles. A wide variety of non-transition metals (Sn, Ga, In, Tl, Zn, Cd, Hg, Sb) exist, among which the most prevalent is Sn.

Simulation of the Crystal-To-Amorphous Transformation in Irradiated Quartz

1990 ◽  
Vol 209 ◽  
Author(s):  
Uma Jain ◽  
Adam C. Powell ◽  
Linn W. Hobbs
Keyword(s):  
Crystal Structure ◽  
Structural Changes ◽  
Interatomic Distances ◽  
Computer Screen ◽  
Bond Lengths ◽  
Orthogonal Coordinates ◽  
Crystalline Matrix

ABSTRACTQuartz and other crystalline polymorphs of silica transform from the crystalline to an aperiodic state under irradiation. There is a need to understand the structural changes involved during this amorphization process. We have built an engineering modelwhich simulates the growth of amorphous regions within a crystalline matrix during the crystal-to-amorphous transition in irradiated quartz. The resulting crystal structure is displayed on the computer screen or plotted on a printer with the orthogonal coordinates of all the atoms in the cluster and the interatomic distances stored in a file. We find the bond lengths increase by about 3%, which is a reasonable value to expect since quartz expands 14% by volume during the amorphization. The results also show the crystal structure surrounding the strained region to be somewhat disturbed, consistent with what is observed experimentally.

Exafs Studies of Group III-Nitrides

1998 ◽  
Vol 512 ◽  
Author(s):  
N J Jeffs ◽  
A V Blant ◽  
T S Cheng ◽  
C T Foxon ◽  
C Bailey ◽  
...  
Keyword(s):  
Phase Separation ◽  
High Frequency ◽  
Group Iii Nitrides ◽  
Total Electron Yield ◽  
Interatomic Distances ◽  
Total Electron ◽  
Group Iii ◽  
Bond Lengths ◽  
Group Iii Nitride ◽  
Comprehensive Study

ABSTRACTThe group III nitrides have important applications for blue/green LEDs, blue/UV laser diodes and for high-power high frequency FETs. In all such devices the alloys play an important role either in the active part of the structure or in the cladding regions. The properties of the group III-nitride alloys are not at present well understood and in particular there are indications that phase separation can occur. We have undertaken a comprehensive study of (InGa)N alloys using EXAFS in order to study such problems.We have demonstrated recently that REFLEXAFS technique can be used to give interatomic distances for (InGa)N alloys using the In edge to measure the bond lengths as a function of In content over the complete range from InN to GaN. We have now extended this study by using the Total Electron Yield (TEY) EXAFS technique to study the bond lengths by using both the Ga and In edges for (InGa)N alloys. The TEY data for the (InGa)N alloy samples gives more reliable data for the In-In and In-Ga separations than the earlier REFLEXAFS studies. Data obtained for the In-Ga separation from the Ga and In edges agree well within experimental error.The data obtained from this study suggest that the (InGa)N samples grown at low temperature do not exhibit evidence for phase separation.

scholarly journals Charge Density Study of two Ni(III) and Ni(II) complexes

2014 ◽  
Vol 70 (a1) ◽  
pp. C1553-C1553
Author(s):  
Peter Herich ◽  
Marek Fronc ◽  
Lukáš Bučinský ◽  
Martin Breza ◽  
Jozef Kožíšek
Keyword(s):  
Charge Density ◽  
Oxidation State ◽  
Central Atom ◽  
Topological Analysis ◽  
Interatomic Distances ◽  
Space Groups ◽  
Bond Lengths ◽  
Square Planar ◽  
Grant Agency ◽  
Lower Oxidation

Experimental charge density of two nickel complexes with oxidation state +3 and +2 of composition (CH3(Ph)3P)+[Ni(bdtCl2)2]-, C31H22Cl4S4P1Ni1 [I] and (CH3(Ph)3P)+[Ni(bdtCl2)2]- dimethylsulfoxide solvate, C25H20Cl2S2P1Ni0.5; C2H6SO [II], (bdtCl2 = 3,6-dichloro-1,2-benzenedithiole ), has been studied. The coordination of Ni central atom by bdtCl2 as a non-innocent ligand gives rise to interesting electronic properties. Compounds I and II crystalize in a monoclinic space groups P 21/c and II in P 21/n, respectively. Their coordination is square-planar with the chromophore [NiS4]. Obvious differences for interatomic distances in metallocycles were found. For I in Ni1-S1-C1-C6-S2-Ni1 there are bond lengths of 2.1534(1), 1.7375(5), 1.4144(8), 1.7327(5), 2.1432(1) Å; and in Ni2-S3-C7-C12-S4-Ni2 there are bond lengths of 2.1453(1), 1.7390(5), 1.4133(7), 1.7387(5), 2.1523(1) Å. For II in Ni1-S1-C1-C6-S2-Ni1 there are bond lengths of 2.1776(2), 1.7437(8), 1.4169(11), 1.7431(8), 2.1663(2) Å. Significantly longer distances for II are in good agreement with the lower oxidation state of central atom. Very accurate data for I an II complexes were obtained with Oxford Diffraction CCD GEMINI R diffractometer at 100K. Multipolar refinement and consecutive topological analysis was performed using XD package. Differences in distribution of electron density in both complexes will be disscussed and compared with quantum-chemical calculations at BP86/VTZP level of theory [1]. This work has been supported by Slovak Grant Agency APVV and VEGA (APVV-0202-10 and 1/0679/11).

Relation between interatomic distances and sizes of ions in molecules and crystals

2002 ◽  
Vol 58 (5) ◽  
pp. 770-779 ◽  
Author(s):  
Viktor Ignatiev
Keyword(s):  
Alkaline Earth ◽  
Alkali Halides ◽  
Surface Layers ◽  
Ionic Radii ◽  
Interatomic Distances ◽  
Bond Lengths ◽  
Dissociation Energies ◽  
Short Range Repulsion ◽  
Alkali Halide Crystals ◽  
Closed Electron

Bond lengths and dissociation energies in alkali halides and alkaline earth oxides and fluorides have been analysed. Ions are considered as static deformable spheres, where an essential part of the electron density is concentrated. In molecules, they are compressed. Moving from molecules to crystals, the bond lengths are extended to such an extent that closed electron shells of ions in alkali halide crystals are separated by distances of ∼20 pm owing to weakened Coulomb attractive forces acting in opposite directions in a crystal. Short-range repulsion is important only within a few surface layers. Some ionic radii are approximately estimated.

scholarly journals On the bond lengths and interatomic distances in certain molecules and crystals

1949 ◽  
Vol 197 (1048) ◽  
pp. 17-27 ◽  
Keyword(s):  
Group Iv ◽  
Single Bond ◽  
Interatomic Distances ◽  
Group Iii ◽  
Bond Lengths ◽  
Triple Bonds ◽  
Long Period ◽  
Whole Number ◽  
Internuclear Distances ◽  
Direct Proportionality

The internuclear distances in the crystals of some of the elements at the absolute zero have been calculated, and the values are examined and compared with those in some molecules. In the first two short periods if the single bond length is denoted D , and the atomic number Z , a direct proportionality exists between D 2 and Z for the members of any one group from group IV to group VII. In groups IV to VII this proportionality extends to the corresponding elements of the first long period, so that, for example, the D 2 values for carbon, silicon and titanium are proportional to Z . In group III the D 2 value for boron and the square of the internuclear distance in the crystal of aluminium are proportional to Z , but the proportionality does no text end to scandium , and in groups I and II no proportionality exists between D 2 and Z . Simple whole-number relations are found between the squares of the internuclear distances in the earlier members of group II, and other regularities are pointed out. Evidence is also given for the hypothesis that simple whole number relations exist between the squares of the bond lengths of single, double and triple bonds of a given element.

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